As far as I'm aware, emails stored in mbox files are not numbered, they are listed one after the other in the order downloaded, so accessing the mbox file could be just as difficult to work out. I use this method. Create a folder on the desktop - call it something like 'TB test'. Highlight all emails in 'Inbox' - use 'Ctrl+A' to do this. right click on highlighted emails and use the 'Save as' option. Save all Inbox emails as '''.eml''' files in that 'TB text' folder. This will store each email as a separate file. Then run scan on the 'TB test' folder. It should then identify exactly which email is causing the issue. Then you can locate that email in 'Inbox' and delete it. Then compact the Inbox to fully remove all traces. Delete the stored eml files in 'TB test' folder and then empty the 'Recycle bin'.